The present invention pertains to hoses and hose manufacturing methods.
Flexible plastic hoses have been made heretofore by winding one or more elongated members formed from polymeric structural materials into a helical structure. Portions of the members on adjacent turns of the helix, referred to herein as "connecting portions," are juxtaposed with one another. The juxtaposed connecting portions typically are secured to one another by a polymeric bonding material, also referred to as a "hot melt". The molten bonding material ordinarily is applied to a connecting portion of a member as that member is wound into the helical structure.
As illustrated, for example, in Richitelli, U.S. Pat. No. 3,199,541, a helically wound hose can be made from a single strip-like member having a U-shaped channel on one edge and a projection on the opposite edge, the member being wound so that the projection on each turn of the member engages the channel on the next turn. In such a construction, the molten bonding material can be deposited in the channel as the member is wound into the helix, and, when cooled, will bond both to the channel and to the engaged projection on the adjacent turn. Another form of helically wound hose employs a channel member and a cap member wound in alternating turns. Typically, both the channel member and the cap member are generally U-shaped in cross-section and are wound so that a first sidewall of one turn of the channel member and a second sidewall of another turn of the channel member are received within the U-shaped cap member. Molten bonding material usually is deposited within the U-shaped cap member during the winding operation. Thus, the bonding material first contacts the interior surfaces of the cap member and then contacts the sidewalls of the channel member as the same enter into the slot defined by the cap member during the winding operation. When the bonding material cools, it solidifies and bonds the mating portions of the channel and cap member together. Hoses made with a "channel and cap" construction are disclosed, for example, in Dillon, U.S. Pat. No. 4,420,019.
Spiral-wound hoses constructed according to these general methods have been used in a wide variety of applications heretofore, such as vacuum cleaner hoses, swimming pool skimmer hoses, flexible low-pressure piping and the like. However, spiral-wound hoses heretofore have been made from relatively soft, low-melting polymeric materials such as ethylene vinyl acetate (EVA). These materials are readily susceptible to fusion under heat and pressure. It has not been practicable heretofore to fabricate spiral-wound hoses with elongated members formed principally or entirely from relatively rigid high melting and difficult to fuse polymeric materials such as high density polyethylene, linear low-density polyethylene, while still employing the molten bonding material technique.